Foodstuff package, process and device for heat-treating a foodstuff vacuum-packed in such a package

ABSTRACT

To find the core temperature of the foodstuff, the package can be fitted with an aperture (3) through which a temperature sensor (11) is inserted into the foodstuff. The temperature sensor is connected to a temperature detection instrument at an end projecting from the aperture (3) and the foodstuff heated to the predetermined temperature, the temperature curve being stored in the temperature detection instrument so as to be fetched. For cooling, the foodstuff with the sensor is, for example, taken out of the oven and reconnected to the temperature detector, in which the temperature curve during cooling is stored so as to be fetched.

The invention involves a food packaging with a sealable wrapping that isflexible, can have the air evacuated and can be heated to at least thepasteurization temperature. Such packaging has been used for a long timein large institutional kitchens to pasteurize food, like vegetables,meat, sauces and similar items, under the brand, "Sous-Vide Bag". Thispackaging is a heat shrinking bag which can have the air removed afterfilling with the item to be pasteurized and then be sealed in anair-tight manner.

A chicken breast can, for example, be pasteurized with such a bag, inthat it is warmed to a core temperature of 75° C. in a suitable oven orwater bath and then cooled as rapidly as possible in an ice water bathof less than 8° C. The process is known as the Sous-Vide Process and hasproven itself, since the cooking loss can be reduced to about 50% underhygienic conditions. There is the problem with this packaging, thatdirect observation and indication of the temperature in the core of thecooked item is not possible.

The invention has the task of creating a packaging of the named type inwhich the above named problem can be avoided. The packaging shouldnonetheless be producible at a favorable cost and completely guaranteehygienic conditions for the food.

The task is solved by a food packaging of this type according to thepresent invention. The packaging of the invention makes possible theemplacement of a temperature sensor which can be introduced into theitem to be pasteurized by means of a simple pass-through. A temperatureacquisition device of a previously known type can be connected to theprotruding end of the sensor and thus register exactly and document thetemperature course in the core during heating and cooling. Thetemperature data can thus be acquired and printed at any time, forexample, in the form of a time/temperature curve or it can be displayedon a monitor. The implanted temperature sensor also makes possible anoptimum control of the temperature course and thus optimum heating andcooling with minimal use of energy.

The food packaging is preferably a bag and in particular a heatshrinking bag capable of withstanding temperatures up to about 110° C.Other variations, however, are also conceivable in which only a partialarea of the packaging manifests a wrapping or a foil. It is essentialthat the pass-through remains sealed after the temperature sensor isremoved.

In another embodiment of the invention the sealing element and thewrapping pulled over it is pushed by a ring. The ring is preferablypositioned on the outside of the wrapping and the sealing element on theinside of the wrapping. This makes possible a simple and hygienicmounting of the pass-through.

The invention also involves a process for heating a food item, inparticular to pasteurize a vacuum-packed food item packaged according tothe present invention, whereby it is warmed, for example, in an oven ora water bath to a predetermined temperature and then is cooled.

Such a process is known in the current state of technology under thename "Sous-Vide Process". It is primarily used in large institutionalkitchens and has proven itself. In this process a food item, like avegetable or meat, is vacuum-sealed in a plastic bag after appropriatepreparation and heated to the pasteurization temperature in an oven orwater bath and then the bag is cooled as rapidly as possible to lessthan 8° C. in an ice water bath or with liquid nitrogen or carbon oxideand stored at 0 to 2° C. It is thereby essential, that the required coretemperature be attained. That amounts for a chicken breast, for example,to about 75° C. This process has the advantage that cooking loss can bereduced to about 50% under hygienic conditions and less vitamins andminerals are lost than was previously the case, and with the above namedtemperature a storage time of at least two weeks can be achieved. Forthe observation of the core temperature it is previously known how toseal a thermometer in the bag which measures the temperature of thecore. The thermometer can be read through the transparent wrapping ofthe bag. The course of the temperature during pasteurization can beobtained by a regular reading of the thermometer and the completion of areport which allows the course of the temperature to be documented.This, however, requires a lot of effort and can only be accomplished ina step-by-step manner. These problems are avoided in the processaccording to a further embodiment of the present invention.

Other advantages can be seen from the following description of apreferred embodiment and the drawings.

An embodiment of the invention will be explained more closely in thefollowing section based on the drawings. Shown are:

FIG. 1a & 1b: A front view and cut-away view of the packaging of theinvention

FIG. 2: The individual parts of the pass-through prior to its mounting

FIG. 3a to 3g: The individual steps for mounting the pass-through

FIG. 4: A schematic partial cut-away of an example of the packaging inthe invention with a mounted thermal sensor

FIG. 5 & 6: A schematic device to perform the process, and

FIG. 7: The temperature course during pasteurization of a food item.

FIGS. 1a and 1b show a bag 1 with food item 2 sealed in an air-tightmanner. The bag basically consists of a foil-like wrapping 14 made ofsuitable, preferably transparent, plastic which is sealed by means ofsealing seams 4. A pass-through 3 for a thermal sensor 11 (FIG. 4) issecured to the wrapping 14 at a suitable location. The pass-through willbe explained in more detail in the following section.

As seen in FIG. 2 the pass-through 3 consists of a hat or plate-shapedsealing member 6 with a circular edge 6a, a ring-shaped projection 6band a recess 6c on the bottom side. To secure this sealing member 6 tothe wrapping, the pass-through incorporates a locking member 5 as wellas a ring 7. As can be seen, the locking member 5 is constructed with ashell-shape and incorporates an inward extending edge 5b and an upperopening 5a. The locking element may be formed from aluminum The ring 7is preferably made of plastic, for example TEFLON, and is so shaped,that the projection 6b engages into the ring 7. The sealing element 6with the ring 7 already emplaced can be inserted from below into thelocking element 5.

The mounting procedure for the pass-through will be explained in thefollowing section using FIGS. 3a to 3g.

The mounting is preferably done while wearing rubber gloves inhygienically clean surroundings. The sealing member 6 preferably made ofnatural non-vulcanized rubber is sterilized in an autoclave prior tomounting. Automatic mounting is, however, also possible.

In the first cut-away view the sealing member 6 is placed in the desiredposition inside the bag. A sack 14a is formed around the sealing member6 on the outside of the wrapping 14, as shown in FIG. 3b.

The sealing member 6 is now pressed together with two fingers and pushedthrough the ring 7, in the direction of arrow 8 as shown in FIG. 3c.

The wrapping 14 is next smoothed out by pulling in the direction of thearrow 10 and the sealing member 6 is pushed into the ring 7, so that thearrangement shown in FIG. 3d is achieved.

The locking element 5 is emplaced from above on the sealing member 6 andthe ring 7, and then the locking element 5 is so pressed using asuitable pressing tool, that it rests tightly on the wrapping 14,sealing member 6 and surrounding the ring 7 with an inward protrudingedge 5b. The bag 1 is thus ready to use and can be filled, have the airremoved, and finally be sealed. The contents of the bag 1 then come incontact with the inside of the wrapping 14 as well as the sealing member6. The locking member 5 may be fixedly connected with the sealing member6 by a form lock. The locking member 5 may also comprise a press-on cap.

To mount the thermal sensor 11 it is pushed through the opening 5a ofthe locking element 5, the wrapping 14 and the sealing member 6 into thecontents of the bag 1. As shown in FIG. 4, the front end 11a extendsinto the food item 2. The external end of the sensor 11 is connected toa temperature indicator 13 by means of a line 12. That device canacquire the temperature at the front end l1a of the sensor 11 andregister it. Such acquisition devices are already known.

In order to pasteurize the food 2, the temperature sensor 11 is insertedthrough the pass-through 3 into the food in such a way, that the coretemperature of the food 2 is measured. The bag 1 with the emplacedtemperature sensor 11 is then placed in an oven 19 or a suitable waterbath and the sensor 11 is connected to the temperature acquisitiondevice 21 by means of a line 22 and a plug 18. The device 21 ispreferably attached to an oven 19 and acquires the temperature presentin the core of the food item 2. The device stores the temperature dataand transmits it to the monitor 17 or a printer via a connection 15 anda line 22. The course of the temperature in the core of the food item 2is displayed on the monitor 17, for example as a curve 20. If thepredetermined temperature, for example 75° C., is reached, the plug 18on the end of the temperature sensor 11 is withdrawn from the device andthe bag 1 with the sensor 11 is removed from the oven 19. During coolingthe plug 18 is again electrically connected to the temperatureacquisition device 21 at a connection 14 on the outside of the oven 19and the bag 1 is placed in an ice water bath 16. The core temperature inthe food item 2 drops here relatively quickly, for example, to 8° C., ascan be seen from the temperature course in FIG. 6. During cooling thetemperature course is displayed on the monitor 17 via the temperatureacquisition device 21 and the line 22.

If the food item 2 has cooled, the temperature sensor 11 is removed frombag 1 and the plug 18 is removed from the device 19. The food item isnow pasteurized and can be further processed in a known manner. Thetemperature sensor 11 is disinfected and used for another activity. Themeasured temperature course is suitably stored and can later bedisplayed or printed. The temperature data and the bag 1 are identifiedwith an appropriate designation, so that even at a later time a check ofthe documentation for the temperature course is possible at any time.The acquisition of the temperature course makes possible a check of theoven 19, whereby safety is further improved and energy use can be keptat a minimum. Storage of the cooled food item occurs in a refrigeratoror walk-in cooling room which guarantees a temperature range of 0 to 2°C. If the temperature range is exceeded, an alarm sounds. In addition,the temperature course is constantly recorded on a so-called "logger"and checked weekly.

We claim:
 1. A package for heat treating a food product comprising:aflexible, vacuum sealable wrapping having an inside portion and anoutside portion; and a pass-through device emplaced on the wrapping,said pass-through device including:a sealing member operable forallowing a temperature sensor to pass through the device and into thefood product; a ring for securely engaging the wrapping against the passthrough device; and a locking member for locking the sealing member,wrapping and ring.
 2. The package according to claim 1, wherein thesealing member is constructed in a plate shape.
 3. The package accordingto claim 1, wherein the sealing member comprises a rubbery elasticmaterial.
 4. The package according to claim 3 wherein the rubberyelastic material comprises rubber.
 5. The package according to claim 1,wherein the locking member is constructed in a shell-shape.
 6. Thepackage according to claim 1, wherein the locking member is manufacturedout of aluminum.
 7. The package according to claim 1, wherein thelocking member engages an edge in a locked configuration with the ring.8. The package according to claim 1, wherein a pass-through opening inthe locking member is disposed over an area of the wrapping, saidwrapping being disposed over an area of the sealing member.
 9. Thepackage according to claim 1, wherein the wrapping is sealed in the areaof the pass-through device at least between the sealing member and thering and between the sealing member and the locking member.
 10. Thepackage according to claim 1, wherein the locking member fixedlyconnects the sealing member to the wrapping by a form-lock.
 11. Thepackage according to claim 1, wherein the sealing member is positionedon the inside portion of the of the wrapping and the locking member isposition on the outside portion of the wrapping.
 12. The packageaccording to claim 1, wherein the wrapping is a bag.
 13. The packageaccording to claim 1, wherein the wrapping is a heat shrinking bag. 14.The package according to claim 1, wherein the locking member is apress-on cap.
 15. The package according to claim 14, wherein the cap ispressed on at least one lower edge.
 16. A process for heating a foodproduct in a package comprising the steps of:providing a food product ina package including:a flexible, sealable wrapping having an insideportion and an outside portion, the food product packed under vacuumtherein; and a pass-through device emplaced on the wrapping, saidpass-through device including:a sealing member operable for allowing atemperature sensor to pass through the device and into the food product;a ring for securely engaging the wrapping against the pass throughdevice; and a locking member for locking the sealing element, wrappingand ring; warming the packed food product in at least one of an oven anda water bath to a predetermined temperature; obtaining a coretemperature of the packed food product using a temperature sensorinserted through the pass-through device positioned in the package, andinto the packed food product, the temperature sensor being attached to atemperature acquisition device to obtain a temperature course during thewarming of the packed food product to the predetermined temperature;removing the packed food product from said at least one of an oven and awater bath; disconnecting the temperature sensor from the temperatureacquisition device; cooling the packed food product; and reconnectingthe temperature sensor to the temperature acquisition device to obtain atemperature course during the cooling step.
 17. The process for heatinga food product in a package according to claim 16 further comprising thestep of removing the sensor from the packed food product after coolingstep and maintaining a vacuum-sealed packaging after removal of thesensor.
 18. The process according to claim 16, wherein during thewarming step, the temperature acquisition device and the temperaturesensor are connected together on an internal surface of the oven orwater bath and wherein during the cooling step, the temperature sensoris replugged with said temperature acquisition device via a connectionexternal of the oven or water bath.
 19. An assembly for heating a foodproduct vacuum-packed in a package, the assembly comprising:a flexible,sealable package containing a food product vacuum packed therein, thepackage comprising: a wrapping, a pass-through device emplaced on thewrapping, said pass-through device including:a sealing member operablefor allowing a temperature sensor to pass through the device and into afood product; a ring for securely engaging the wrapping against thepass-through device; and a locking member for locking the sealingelement, wrapping and ring; a temperature sensor insertable through thepass-through device in the wrapping and into the food product; and atemperature acquisition device attached to at least one of an oven and awater bath and connected to the temperature sensor to acquire atemperature course.